In response to trends in energy conservation, demands for illumination or backlight using an LED are increasing recently. The LED used therein is a white light-emitting LED in which phosphor is disposed on an LED chip which emits blue or near-ultraviolet wavelength light. For this type of white light-emitting LED, the one in which a phosphor, which emits yellow or orange light using the blue light from the blue LED chip as an excitation light, is provided on a blue LED chip, is recently being used. An even better emission efficiency is demanded for an LED, and a phosphor which excels in emission characteristics is desired for a yellow or orange phosphor.
A YAG (yttrium aluminum garnet) phosphor is known as a yellow phosphor, and Patent Literature 1, for example, discloses that emission characteristics of a YAG phosphor are improved by using flux.
As another yellow or orange phosphor, Patent Literature 2, for example, discloses an α-sialon phosphor, which is expressed by compositional formula Sr1.11Al2.25Si9.75N16:Eu0.02.